Composite bone-implant engineered with magnesium and variable degradation for orthopaedics

Abstract

Metallic biomaterials are suitable for load-bearing scaffolds, and magnesium (Mg) alloy is the most preferable because of its mechanical properties are comparable to those of hard tissue (bone). The most important characteristic of an implant is its biocompatibility and Mg fully satisfies this standard. Mg is also biodegradable, thereby avoiding the need for secondary surgery. An uncontrollable degradation rate is one of the most significant limitations of magnesium-based implants, which hinders their applications in bone tissue engineering. Hydroxyapatite (HAP), a bioactive material, was incorporated into a magnesium metal matrix as a catalyst for enhancing bone tissue regeneration. Porosity in the scaffold could serve as a conduit for nutrients and also aids in the scaffold's weight reduction. This study investigated the effect of selective alloying elements (Ca, Zn, and Fe) on the biodegradability of scaffolds. Powder metallurgy was used to produce the magnesium alloy scaffolds. A calculated quantity of porogen particles, carbamide (urea), was incorporated into the Mg-Ca-Zn-Fe matrix in order to achieve 30% and 50% porosity. Due to the formation of Mg-Ca-Zn-Fe intermetallic compounds, the current study establishes that Mg alloy-based samples exhibit favorable biodegradation behavior. After seven days of immersion, the pH of the immersion liquid had also been found to have stabilized. Consequently, the observations suggest that the biodegradation behavior of bone implants could be modified by developing composite porous magnesium alloy implants.